The Warburg effect describes a pro-oncogenic metabolism switch that cancer cells take up more glucose than normal tissue, yet use less glucose for oxidative phosphorylation and favor glycolysis even in the presence of oxygen. However, how crucial this is for pathogenesis and disease progression in human cancers remains unknown. We approached these questions by examining whether tyrosine kinase signaling - commonly upregulated in tumors - regulates the Warburg effect to contribute to tumorigenesis and maintenance of the tumor. This hypothesis builds on our observation that a spectrum of key protein effectors of glycolysis and oxidative phosphorylation are regulated by tyrosine phosphorylation in leukemia cells expressing FGFR1 fusion tyrosine kinases, which are associated with 8p11 stem cell myeloproliferative disorder (MPD). These protein factors include pyruvate kinase M2 (fetal) isoform (PKM2), lactate dehydrogenase A (LDH-A), and pyruvate dehydrogenase kinase 1 (PDHK1), which work together to tightly regulate the metabolic pathways in cells. Thus, our overall hypothesis is that oncogenic FGFR1 promotes the Warburg effect and tumorigenesis by reprogramming cancer cell metabolism in an acute way via phosphorylation of PKM2, PDHK1 and LDH-A. In this proposal, we will use oncogenic FGFR1-associated 8p11 MPD expressing active FGFR1 fusion tyrosine kinases and lung cancer overexpressing FGFR1 as platforms. Three Specific Aims are proposed: (1) To elucidate the molecular mechanisms by which FGFR1 reprograms cancer cell metabolism through direct phosphorylation of PKM2, PDHK1 and LDH-A; (2) To determine whether FGFR1-mediated phosphorylation of PKM2, PDHK1 and LDH-A promotes the metabolic switch to aerobic glycolysis from oxidative phosphorylation in cancer cells; (3) To determine whether FGFR1-mediated phosphorylation of PKM2, PDHK1 and LDH-A provides a metabolic advantage to tumor cell proliferation and tumor development. We will test the aforementioned rescue cell lines for dependence on glycolysis to proliferate and ability to form tumors in murine models of cancer.